Indicator for automatic slowness testers



April 10, 1928.- 1,666,034

M. O. SCHUR INDICATOR FOR AUTOMATIC SLOWNESS TESTERS Filed Jan. 25. 1926 5 Sheets-Sheet l April 10, 1928.

M. O. SCHUR INDICATOR FOR AUTOMATIC SLOWNESS TESTERS 5 Sheets-Sheet 2 Filed Jan. 25, 1926 April 10, 1928.

M. O. SCHUR INDICATOR FOR AUTOMATIG SLOWNEISS TESTERS Filed Jan. 23, 1926 5 Sheets-Sheet 3 April 10, 1928.

M. O. SCHUR INDICATOR FOR AUTOMATIC SLOWNESS TESTERS Filed Jan. 23. 1926 5 Sheets-Sheet 4 L I, hr w 5 Sheets-Sheet 5 April 10, 1928.

M. O. SCHUR INDICATOR FOR AUTOMATIC SLOWNESS TESTERS Filed Jan. 23, 1926 Patented Apr. 10, 1928.

UNITED STATES PATENT oF'FlcE;

HILTON 0. 805173, BERLIN, NEW HAMPSHIRE, ASSIGNOB 1'0 BROWN 001mm, OI

BERLIN, NEW HAHPSHIRE,

A CORPORATION OF nnnu.

INDICATOR FOR AUTOMATIC BLOWN! TESTERS.

Application filed January as, 1926. Serial No. 03,324.

This invention relates to means for record; ing continuously the product of two variable quantities during the variation of either,.

or both, within certain limits. It also re:- 5 lates to mechanism, associated and concurrently operated with the. recording means for-keeping constant the ratio ofthe-twoya- -.riables-' for controllinga factorr-or cond t on on which said ratio depends, as for example,

I0 automatically controlling the character of li uid suspensions of, solid material.

- ore specifically, the invention, is designed to'p'rovideboth'an improved recorder for use with the automatic, slowness tester 5-, described in my application Serial No. 721,-

246, filedJune 20, 1924, and also improved. means for, keeping substantially constant the concentration of an aqueous suspension of-cellulosic fibers or material for the testing of which -my slowness "tester-1 is idesigned. But it is to be understood that the scope and applicability of the invention are not limited to theiparticular art or machine.

- pending liquid is of great importance in the art, of paper making, since the quality of the paper will depend in large measure thereon, this being dependent on the degree to which the pulp has been beaten; The process of.

beating serves usually to decrease the freeness of'the stock and: to increase the strength of the aper made therefrom (upto' a certain point), to give a'f-more even texture to 40 the paper, and to reduce the probability of I the formation of wild sheets. Pulp w ich is beaten behaves as if the process of beating coated the fibers increasingly with a mucilaginous substance, the result being that water flows more readily through pulp which has had less beating. Consequently, the rate of flow through a mat of given thickness is a measure of the freeness of the ulp, other factors afiecting the rate offlow ing constant. It will be readily under-v stood that any apparatus capable of measuring the freeness of pulp with be equally available for measuringthe slowness or resistance to the flow of theliquid by a mere change of scale since the two characteristics have a simple reciprocal relation to each other. On account of the increase in slowness caused by beating, too much beating will'not only result in a waste of ener h in running the beater, but will cause t e pulp mat to form more slowly on the-Four-iw Adria a-sate n;t usj -n si tingi pslQ w operationot, the pa 'er- 'naliingmachine for a heating of the pa p; mixture to resequent ,vgaste 0 s Qam. Anot erresult o f" beating the! nip beyond the desiredzgllwlint g5 'freeness. is t at, the character. of the paper w ll be alteredthereby. "Hence, for ,the econoiplcal and efiici ent operation of a form product, it is. necessary to keep track papermaking machine, as well as for a uni-.

of and regulate the freeness (or slowness) h of the pulp.- q I In the application mentioned above is disly the freeness of a ulp suspension ref- .erably when-passing i p As therein closed -a device for indicating continuouspr'oduct of therate of flow of whitewater (the water which has passed through the mat) by the" thickness of the mat, provided the viscosity of thewater and the hydraulic head bekept constant orcompensated for.

Since the viscosity-of water varies sharply with the temperature, the-temperature and level of. the pulp mixture in the vat must be kept constant or reduced to standard. Itis'cle'ar that if either the. thickness. of 'the mat on therate of flow of white water is also kept constant, a measure of the other with the "proper units will be aimeasure ofathej freeness or slowness. It is prefer able, however to provide for concurrent variations in b using a watermeter of the capillary type, variations in temperature can be disregard- .ed since the mass of capillaries through *which the white water passes in such ameter through the pulp mat and through the capillaries and therefore would not have to be corrected for. It is preferred, however, to use a meter of the. orifice type .as will be-here- 0th of these, quantities. By

fter described, which type of meter is l-lll.

10ovirtually reproduces the porous structure of relatively unresponsive to changes in viscosity, hence it is important to maintain a constant temperature when using this type of meter. u

By the resent invention simplified means are rovi ed for continuously recording the pr uct of the two concurrent variables, comprising the rate of flow of white water and the thickness of the mat of pulp formed on a Fourdrinier screen. In the recording device disclosed in the previous application, logarithmic spiral cams were used. Itns difficult and ex nsive to out such cams with the necessary egree of accuracy. My 1mproved recording device does away with the necessity for such cams and may be constructed of simple and relatively inexpensive parts. The recording device may also be electrically connected to repeat the lndlcations at any desired distance, to control the beating engine or other machinery desired, to give Warning signals when the character of the pulp reaches certain limiting conditions, or to perform any combination of the aboveor other desired functions simultaneously.

By this invention also improved means are provided for regulating the stock density. in the vat of the testing apparatus. Since the water'supply to the vat must be regulated to maintain a constant level in the vat, the stock density is controlled by varying the rate at which pulp is admitted to the vat from the beatmg engine. Although the measurements of freeness or slowness in the manner described above are independent of the stock density within comparatively wide limits, yet it is desirable to maintain a reasonable uniformity of stock density in the vat. Mathematical calculation, checked by experimental results, has shown that the stock density is measurable by and proportional to the thickness of the pulp mat divided by the rate of flow of the White water. Novel mechanism is therefore provided according to this invention for regulating the admission of pulp to the vat which is responsive simultaneously to variations in the thickness of the pulp mat and therate of flow of white water. This results in a stock density in the vat which is fairly constant.

Further advantageous features and combinations will be found in the following description of the device and in the drawings, in which Fi re 1 is a general view in elevation of t e recording mechanism and a part of the mechanism for regulating the stock density.

Figure 2 is an elevation of a slowness testing device with which the present in-- vention is adapted for use. A conventional beatin engine of the Jordan type is indicate on a reduced scale.

Figure 3 is a pers ctive of a meter for measuring the flow o the white water.

Fi ure 4 is a side elevation of the record- Figure 11 is a transverse section of the cylinder.

Figure 12 is a detail of a hunting mechanism used to make the indicating devices res ond to variations in the thickness of the pn mat.

i ure 13 is a diagrammatic showin of the ectric wiring used with the recor ing device.

Figure 14 is a diagrammatic showing of modified form of that part of the wiring system relating to the control of the motors used in the apparatus.

Referring in detail to the drawings, Figure 2 indicates an automatic slowness or freeness testing device for pulp suspensions for use with which the present invention is particularly suited. A brief description of the construction and operation of'this tester will- 'be given, but for a more complete showing and description of the details of structure, reference is had to my copending application Serial No. 721,246, filed June 20, 1924.

A vat or container 1 for the pulp suspension is suitably located to receive pul to be tested from the beating engine 2 (w ieh is shown in the drawing for convenience on a reduced scale) through the which the pulp from the beating engine passes through a sampling box a and pipe 5 to the stoc chest. A portion of the pulp passing through the sampling box is admltted through a gate valve 6 and passes into the vat through a supply pipe 7. The means for controlling the admission of pulp to the vat will be described later.

In the determination of the freeness of the stock, a mat of pulp iscontinuously formed on the submerged portion of a horizontal cylinder mold 11, indicated in outline in Figure 2, on the surface of which is a Fourdrinier screen 12, as the cylinderis rotated at a substantially constant speed. The pulp suspension is kept at a constant level to maintain a constant hydrostatic head, the preferred level, as shown in the drawing, bisecting the cylinder. This constant level-is preferably maintained by the admission of water througha supply pipe 13, the flow being regulated as by a valve 14 operated by a diaphragm motor 15 controlled by a float 16 and a valve 17 and by Hit! an overflow conduit 8, the mouth 9 of which is positioned on a level with the center line of the cylinder mold 11. motor 15 may be operated by air, or any other suitable fluid under pressure. The float 16 is preferably so adjusted that when the suspension in the vat is at normal level,

there will be a small inflow of water through the pipe 13, thereby insuring a constant hydrostatic head and a sufficient circulation of stock in the vat even when the stock is very slow.

The stock in the vat is kept from settling by agitators 18 mounted on a shaft 19 which is driven from any convenient source of power 20.

To facilitate accurate measurement of the pulp mat, an endless apron 21, supported on a plurality of rolls 22, is led over a portion of the cylinder mold in such a way as to engage the pulp mat immediately after its formation beneath the surface of the suspension and to pass between the pulp mat and the movable measuring roll 23 which is adapted to move in a vertical direction in response to variations in the thickness of the pulp mat, being guided by links 24 which may be mounted in such a way as to counterbalance most of the weight of the roll 23, so that a light uniform pressure is maintained on the apron and the pulp mat beneath it, the pressure bein reproducible for succeeding runs of pulp w en the operation of the tester is intermittent. The cylinder 11 and preferably'one or more of the rolls 22 may be operatively connected with the power source 20, or may be driven at a substantially constant speed by any other desired means. When a constant speed is maintained, the measurement of the thickness of the mat is also a measure of the rate of removal of pulp from the suspension. The apron 21 is preferably made of a strip of thin, transparent, practically incompressible material, such as celluloid, and serves to compress the pulp mat evenly, to prevent wrinkling of the mat,

to prevent the measuring roll 23 from sinking into the soft mat and thus engaging it with varying pressure, and to prevent the mat or portions of it from adhering to the measuring roll. The incompressibility of the apron is necessary for precision in measuring the thickness of the mat, While its transparency permits observation of the mat. The presence of pulp on the apron between it and the roll 23 which would add a false thickness to the mat is prevented as by suitable jets of water directed against the upper 7 surface of the apron as it emerges from the suspension in the vat by nozzles 25 connected to a supply pipe 26.

The movement of the roll 23 through the intermediacy of a hunting mechanism generally indicated as 27 controls a mechanism,

The diaphragm hereinafter described, for automatically indicating the thickness of the mat. A suitable hunting mechanism is illustrated in detail in Figure 12. As shown in Figure 10, a flexible element 28 is connected with the roller 23 so as to rise and fall therewith. Its upper end, as shown in Figure 12, is secured to an end of a short cross-piece 29 WlllCh is also supported by a' flexible member 30 positioned parallel to the member 28 and fixed to an arm 31 on a nut 32. This nut is threaded on a screw shaft 33 which is su ported for rotation by bearings 34 and 35 in the frame 36. The nut 32 is constrained from rotation so as to travel on'the shaft 33 as the latter turns. Extending upwardly from the cross-piece 29 and fixed thereto is a fork 37, the tines of which straddle a pin 38 fixed on a block 39 pivotally hung from a bracket 40. This bracket also supports spring contacts 41, 42 and 43, so arranged t at motion of the fork 37 will swing the block 39 against either one of the contacts 42, pressing it against the adjacent cont-acts 41 or 43 and closing a circuit to operate a motor 44. It will readily be seen that by making the cross-piece 29 relatively short and the fork 37 relatively long, any slight longitudinal motion of the flexible member 28, such as would be occasioned by a change in the thickness of the pulp mat, will result 1n a greatly magnified motion of the tines of the fork 37 so that the circuit-closing device described above may be made very sensitive to slight motions of the flexible member 28;

When the equilibrium of the system is upset by a change in mat thickness, so as to start the'operation of the motor 44 in one direction or the other, the motor turns the shaft 45, which through a worm 46 and gear 47 turns the screw shaft 33, causing the nut 32 to travel up or down a distance equal to the displacement of the member 28. This follow-up movement of the nut 32 levels the cross-piece 29, and returns the fork 37 to its normal position, thus breaking the electrical circuit, and stopping the motor 44. As will hereinafter be described, the motor 44 also operates indicating mechanism which is thus responsive to the thickness of the pulp mat.

The pulp mat after passing under the roll- 23 and being measured is cut up as by jets from suitable nozzles 48 and removed from the Fourdrinier screen as by jets directed against the inner surface of the screen from within the cylinder, the pump being caught as by a doctor 49 and carried off through a drain 50. During the formation of the pulp mat on the lower portion of the Fourdrinier screen, a'constant reduced pressure is maintained within the cylinder mold by any suitable means, so that the suspending liquid is drawn through the mat and the screen, and flows out through pipe 51 into a flow meter, which includes a receptacle indicated at 52 and which will be described later. i

I will now describe a preferred construction of the cylinder mold 11 with connected apparatus for maintaining a constant hydrostatic head on the pulp mat during its period of formation on the Fourdrinier screen. This construction is illustrated in Figures 10 and 11 wherein the cylinder 11 is shown as mounted for rotation on a stationary plug 53 which is preferably tapered. The cylinder preferably consists of a bronze shell whichis provided with a large number of equally spaced radially disposed longitudinal slots which widen or diverge outwardly to form knife edges at the periphery of the roll about which a screen or strip of Fourdrinier wire is tightly wound. v Preferably the screen or wire is formed in a narrow strip which is wound helically about the cylinder, the edge of successive convolutions of the strip abutting together so as to present no protuberance on the periphery of the mold. The tapered ends of the strip are soldered to the unslotted end portions of the shell, the soldered parts being overlapped and covered by a pair of rubber deckles 54, one of which abuts against a peripheral flange 55 of the shell. The other deckle abuts against a removable collar 56 which is secured to the end of the shell opposite to that on which the flange 55 is formed. Removal of the collar 56 permits the removal or replacement of the deckles 54. Any suitable mechanism may be provided for rotating the cylinder at constant speed. For example, a worm gear57 may be secured to one end engaging a worm 58 on a shaft 59 which may be connected in any preferred manner to a suitable source of power. The worm and gear are preferably enclosed in a suitable housin 60 mounted on fixed supports (not shown l. The shell of the cylinder and the plug 53 have a ground and lapped fit so as to form an air-tight and water-tight joint. Provision is made for adjusting the plug axially relatively to the shell to compensate for' wear and to maintain the water-tight joint between them. To this end, there are placed upon threaded portions of hub members 61,

62 of the plug clamp nuts 63, 64, which;

'maintained in the pipe 77 by any suitable.

bear against the ends of the shell. By rotating these nuts in one direction or the other, the plug may be adjusted lengthwise of the shell. 7 Each clamp nut is split, and its sections may be drawn together by bolts 65, 66, thereby tightl clamping the nuts on the hubs 61, 62. he plug is supported by its hubs on standards 67, 68, which are fixed to suitable framework (not shown), and is held againstrotation b cap clamps 69, 70. The hubs 61 and 62 o the plug are hollow, the interior of the hub 61 communieating with a chamber 71 within the 0 limder by a port 72, and the interior of the hub 62 communicating with a chamber 73 within the cylinder mold by a port 74. The chambers 71, 73 are formed between the shell of the cylinder and the plug by recesses in the plug. The level of the pulp suspension in the vat being kept at the axis of the cylinder mold and of the plug, the latter is so arranged that the chamber 71 is above the level of the stock suspension while the chamber 73 is below it. Suction is maintained in both these chambers as the cylinder is being rotated so that the water component of the stock suspension which passes through the mat of pulp formed and being formed on the submerged portion of the Fourdrinier screen 12 and through the slots in the shell of the cylinder mold flows outwardly through the hub 62 and down the vertical conduit 51 to the water-meter tank 52. It is desirable that suction be maintained in the chamber 71 for several reasons; first, to prevent any possibility of leakage of air from this chamber past the joint between the shell of the cylinder mold and the plug into the chamber 73; second, to hold the mat of pulp on the screen as the latter rises above the level of the suspensions in the vat; third, to prevent the mat from being picked up by the apron 21 after engagement with the latter during a portion of its travel on the cylinder mold. Means are provided for maintaining a balance between the suctions in the chambers 71 and 73. The hollow hub 62 connects with the vertical conduit 51, part of the connection being a glass tube 75 for purposes of observation. The hollow hub 61 opens into a discharge conduit 76 which extends vertically downward and is slightly longer than the conduit 51, its lower end extending beneath the surface of water in a suitable receptacle not shown, whereby under a vacuum sufficient to keep the siphon comprising the hollow hub 62, the chamber 73 and the conduit 51 full of water, the Water will not rise in the conduit 76 sufficiently to interfere with the draining of the chamber 71 through the hollow hub 61.

A balanced suction is maintained in the chambers 71 and 73 through a pipe 77 which "isconnected to both the conduits -51 and 76 by fpipes 78 and. 79. A constant suction is into the i pi es 78 and 79. This suction may be maintamed substantially constant by supplying air to the tank 83 as needed to prevent an excess of. suction. The admission of air may be regulated by mercury seal 84 in a closed tank 85 with which the pipe 82-com-- municates. An air inlet pipe 86 extends below the surface of the mercury to a depth oorrespondin to the suction desired in they tank'83, as W111 be readily understood from of the t the drawing. Any water which may be drawn into the tank83 will be carried off by a drain pi 87 which leads from the bottom an; downwardly into asnitable water trap. It is obvious that with the construction described above, the aspirator 80 will be capable of maintaining a constant-balanced suction in the chambers 71 and 73, the chamber 73 and the siphon associated with it being-kept full of water and the chamber 71 drained, and will thus provide fora constant hydraulic head on the white water flowing through the pulp mat, which is highdesirable in. making measurements of freeness or slowness.

its

For removin the pulp mat from the screen 12 after it has passed under the measuring roll 23, a supply of water is led in through a pipe w '0 may, as shown, enter the hollow interior of the hub 61 and extend coaxiall therewith to a central recess 88 in the p ug 53. Suitable passages lead radially outward from the recess 88 from which the water emerges in jets 89 through the .ongitudinal slots and the Fourdrinier screen, completely washin the pulp from the passin' surface of the atter.

ith certain types of flow meters, such as the one which W111 be hereinafter described, it is important that the temperature of the liquid passing through the pulp mat be maintamed substantially constant. This is because the viscosity of liquids, such as water, varies sha l with the temperature, and the rate o f flow of a liquid through the capillary pores of the mat .is very sensitive to changes in its viscosity, whereas in a flow meter having a single relatively large exhaustport by passage through which the flow is measured, the effect of variation in the viscosity of the fluid is relatively small. To maintain the contents of the vatat a constant temperature, steam may be supplied through a perforated pipe 90 and valve 91 which is controlled through a diaphragm motor 92 by a thermo-responsive element 93. The pulp suspension may, if preferred, be warmed by heating coils, but the direct introduction of steam into the mixture has been found satisfactory. It is preferred to maintain the suspension at a temperature slightly higher than the maximum temperature of the river water used in the mill, so that by more or less heating as conditions may require a constant. temperature may be effected. A suitable flow meter for measuring the rate of outflow of the white water after it has passed through a The white water entering the recegtacle or tank 52 throu' h pipe 51 passes be e plates ;94 and 951m drains out through an openin 96 in the form of a semicircular slot, w lab 18 accurately cut in a plate 97 .set into the bottom of receptacle 52 and is' carrled off by dram pipe 98. The baffle 95. with a partition 99 constitute a water seal and 1 prevent air working back to the pipe 51.

The rate of flow of white water is meas-- ured by the amount of opening of the slot 96, through which the white water passes out from the tank 52, necessary to balance the inflow through the pulp. mat and the pipe 51 and maintain a constant level in the tank 52. ThlS level is .maintainedat normaT by automatic mechanism including .a'. float 100 which controls a motor 101 operating a shutter 102 to increase of diminish the amount of opening of the slot 96.. The float 1001s located in a com artment of' the receptacle 52 formed by t e partition 99 and a perforated portion of the baflle 95. The

float controls the motor 101 through a flexible member 103 which connects it with an arm of a lever 104 shown in Figure 1 in the form of a T, mounted on a-knife-edge support 105. On the opposite side of the support, a. weight 106 1s provided to counterbalance the float 100 and the flexible member 103. v The long arm 107 of the lever carries an electric contact point 108 which contacts with point 109 or 110 to close a circuit to operate the motor 101 in one direction or the other according as the float 100 ris.es"or falls. The point 108 is insulated from the lever 104 by a cap 111 of fiber or any desired insulating material. A fine insulated wire 112 is led from the point 108 along the arm 107 and leaves it through a spring coil 113 near the support 105 to connect point 108 with the motor 101 and a source of electrical en-' ergy. The motor 101 is operatively connected by suitable shafts and gearing both to the shutter 102 and to a' threaded shaft or rod 114 on which a nut 115 is held against rotation so as to travel longitudinally of the shaft 114 when the latter is rotated. The motion of the nut 115 is thus concurrent with the motion of the shutter 102 and its .positiori on the shaft 114 is a measure of gears 118 and 119, the latter beingfixed to the shaft 114. To connect the motor further with the shutter 102, a gear 120 is mounted on the shaft.114 meshing with a gear 121 mounted on a shaft 122 which turns a shaft 123 througha worm and gear 124. The shaft. 123 through a worm and gear 125 turns the shaft 126 on which the upper edges.

shutter 102 is fixed. The slot 96 is cut in a late 97 which is fitted in the bottom of the Bow-meter rece tacle 52 and on the upKr surface of whic the shutter 102 slides. e shaft 126 extends through the plate 97 and a light spring 127 on its protruding end serves to kee the shutter 102 snugly against the face the plate 97. The slot 96 is preferably cut wit ajtra ezoidal cross section, the narrower portion ing uppermost so that the water in passing. out touches only the It has been shown experimentally that the rate of flow of water through a slot of that kind with uniform width isdirectly proportional to the angular amount of opening where the slot is in the shape of a circular arc. The motion of the nut 115 on the shaft 114 being proportlonal to the motion of the shutter 102 is also prortional to angular amount of opening of the slot 96,hence the position of the nut 115 is a measure of the rate of flow of the white water from the cylinder 11. If desired, this rate of flow can be directly indicated-on a scale 128 by mounting an index 129 on the nut 115 and fixing the scale in a convenient sition behind the index and parallel to t e shaft 114.

The mechanism for' indicating the thickness of the pulgiemat formed on the cylinder 11 will now described. As.- previously stated, vertical movement of the roll 23 produced by variations in the thickness of the pulp mat o crates a hunting mechanism WlTlCh contro s the rotation of the motor 44. This motor through a suitable set of reduction gears, generally indicated at 130, drives a threaded shaft or rod 131 supported at right angles to the shaft 114 in 'bearings132 and 133, a reduced end 134 of which shaft is geared to the shaft which is connected with follow-up mechanism (described above) for restoring the hunting device to its nor? mal position, after it has been displaced by a variation in the thickness of the pulp mat vto start operation of the motor 44 in one direction or the other. Mounted parallel to shaft 131 and geared thereto bequal gears 135 and 136 is a similar threa ed shaft 137. As shown in Figure 5, shafts 131 and 137 support acarriage 138 threaded thereon to move longitudinally thereof when the shafts 131 and 137 are rotated. The shaft 137, if preferred, may be made smooth for sliding engagement with the carriage 138, dispensing with the gears 135 and 136. Since a displacement of the hunting element in the unting mechanism by a vertical movement of the roller 23 responsive to a' change in the thickness of the pulp mat re uires rotation of the motor 44 to restore the unting element to normal position, and since the rotation of the motor 44 at the same time moves the carriage 138 along the shaft 131. the position of the carriage 138 on the shaft 131 is thus a measure of the thickness of the pulp mat. 7

It is evident that a. inter 139 on the carriage 138 and a sea e 140 fixed parallel to shaft 131 can be used to indicate the thickness of the mat in any desired units.

To rovide a scale and means for automatica lg indicating thereon the product of rate of ow of white water by the thickness of the pulp mat as a measure of the freeness of the pulp, two parallel slotted plates 141 and 142 are secured to the carriage 138 and depend vertically therefrom. Fixed to the carriage 138 in front of these plates is a plate' 143 graduated with suitable scale.

markings. A rider 144 is mounted to slide lengthwise of the graduated plate and is'provided with oppositely dis osed inters 145 to indicate the position 0 the rider relative to the scale on the graduated plate. The rider 144, as shown comprises a member 146, preferably of meta which has a central boss 147 to roject through the slots in the plates 141 an 142. A rin or roller 1481's mounted on, the boss to ri e between the plates 141 and 142. The rider is retained in slidable relation with the plates 141, 142 and 143 by a pair of nuts 149 and 150 on the threaded outer end of the boss.

the member 146 are fixed blocks 151 of in- On the front face of sulating material, such as fiber, the pointers 145 also being preferably of the same material. These blocks support spring contacts 152 and 153 which have a sliding contact with wires 154 and 155 respectively, and are electrically. connected'by a wire 156, which wires are a part of a recording stem and will be referred to hereinafter 1n the description of the wiring diagram of Figure 13. Y

roller 148 engaging the sides of the slot in Q the link member 157 and fitting closely therein; The slot of the link member 157 also engages closely a pin- 158 on the traveler 115, so thatmotion of the traveler 115 along the shaft 114 will swing the link member 157 on its pivot A, and will thus determine the angle which the link 157 makes with the shaft 131 at A. The motion of the lever 157 also may impart motion to the rider 144 up or down the scale of the plate 143. When the shafts 131 and 137 are rotated, the carriage 138 is constrained to travel lengthvwise thereof and in a direction transverse to the plate 143. The carriage 138 in its motion carries with it the plates 141 and 142 which also may impart motion to the rider 144 up or down the scale, the amount of such 'motion of the rider 144 corresponding to a given motion of the plates 141 and 142 depending -on the angular relation between the link 157 and the shaft 131. It is measures the mat thickness, and the traveler thus obvious that the rider 144'is responsive to motion of both the carriage 13.8, W-h1ch 115, which measures the outflow of white water. That the position of-the rider 144 on the scale member 143 may bean indication of 'the product of the mat thlckness by the Outflow of the white water is shown b reference to the properties of similar triangles which inthis case are defined by the projection onto a common plane of the axes of the shafts 114 and 131, and of the center lines of the link member 157 and the scale late 143, as on the plane of the paper in igure 1 of the drawing. These prolected lines intersect at points A, B, C, D and E, the point A also being in the pivot axis of Since AB here is a constant quantity, it is seen at once that DE is proportional to the product of AD and BC. Since in the mechanism shown, AD is a measure of thlckness of the pulp mat and BC is a measure of the rate of outflow of white water, DE will be a measure of. the product of these two quantities, hence of the freeness of the pulp. The scale may be calibrated with any convenient units desired, and when it is used to indicate freeness of the pulp, the markings'will be j equally spaced. It is obvious that it may also be calibrated to read in terms of the slowness of the pulp, in which case the spacing between successive graduations' of the scale willincrease as they descend, since the slowness is not directly but inversely proportional to the product of the thickness of that by the flow of white water. If desired, two scales may be marked on the plate,

one reading n terms 'of freeness, the other the rate of admission of pulp into the vat in terms of slowness.

.It is also obvious that if the outflow of white water be kept constant, the length of' DE, determined by the position of the rider 144 on the scale member 143, will be a measure of the thickness ofthe pulp mat as well as of the freeness of the pulp and the scale 143 can be calibrated accordingly to read in terms of mat thickness for any given rate" of outflow. Likewise, if the mat thlckness be kept constant, the length of DE will be a measure of the rate of outflow as well as of the freeness of thepulp, and the scale can be calibrated accordingly to read in terms of outflow for anygiven thickness of the mat.

Figure 6 shows a means for preventing endwise play in the shafts 11 4, 131 and 137.-

Each of these shafts atone end has a re- I duced portion 159 on which is rotatably mounted sin-externally threaded sleeve 160 which is threaded through an aperture in the member supporting that end of the shaft. Thesleeve 160 is provided with a .knurled head 161 by which it is turned and thus setup against a shoulder 162 on the shaft; holding the shaft against lengthwise motion. A nut 163 is used to lock the sleeve 160 in adjusted position. I

To avoid damage to the apparatus in case:

any part fails to function stops are provided to shut off the current from motors 101 or 44 when the traveler 115 or'the carriage 138' has reached a limiting properly, limit position at either end of the shaft on which it travels. These limit stops are preferably in the form of electric switches 164, 165,

166 and 167. On the traveler 138 are mounted two members 168 and 169 which engage sw1tches'164 and 165, respectively, when the traveler ing the motor 44 with its Figure 13. In like'manner, members 170 and .171 are mounted on the traveler 115 to 101 with itssource of of flow of the-white water varies closely with the concentration of pulp in the suspension. It will be seen therefore that the pulp suspension may be kept substantially constant by employing ineans which tend to decrearie when the thickness of the pulp mat increases, and to increase the inflow of pulp as the rate of flow of white water increases, and vice versa.

The shafts 114 and 131, which are responsive to changes in'the flow of white water and mat thickness, respectively, are utilized to control the admission of pulp into the vat as'fiillows. The pulp is admitted from the sampling box 4 through the gate valve 6 which is controlled through a diaphragm motor 172 by the relay valve indicated as 173. The mechanism for operating the relay valve 173 is shownin Figure 4, some of this mechanism being omitted from Figure 1 to prevent confusion of detail. Referring to 138 reaches its corresponding limiting posltion and breaks the circuit connectsource of power, as may be seen from the wiring diagram in breaking the circuit con- Figures 1- and 4, it will be recalled that a change of thickness in the pulp mat results in the rotation of shaft 131. This shaft is geared to a vertical shaft 174 by bevel gears 175 and 176. Fixed to the shaft 174 is a gear 177 which meshes with a gear 178. A vertieal shaft 179 has a reduced portion 180 sliding in a bearing in a bracket 181. c The lower portion of shaft 179 is threaded and has a slot 182 extending lengthwise thereof (Figure 9). This shaft passes through the brackets 183 and 184, gear 178 and car 185. The gears 178 and 185 are spaced rom the brackets 183 and 184 and from each other by suitable collars 186 loosely surrounding the shaft 17 9.

It will also be recalled that a variation in the flow of White water will result in a ro-- tation of the shafts 114 and 122. Fixed to the shaft 122 is a gear 187 meshing with the gear 185. Hence a variation.in the thickness of the pulp mat will cause a rotation of the gear 178, while a variation in the flow of white water will cause a rotation of the gear 185. The gear 178 is bored out and a bushing. 188 is fixed therein which fits snugly about the shaft 17 9 and has a lug formed 1ntegrally fitting into the slot or groove 182 in the side of the shaft 179 so that the shaft 179 is free to slide lengthwise with respect to the gear 17 8, but is constrained to turn with that gear. The gear 185 is threaded on the shaft 179. As will be seen from Figure 9, rotation of the gear 185 will result in longitudinal motion of the shaft 179 provided the shaft is restrained from rotation. Likewise if the gear 185 is held fixed and the gear 178 is rotated, the shaft 17 turning with the gear 178 will move longitudinally by reason of its threaded engagement with the gear 185. Since the gears 178 and 185 are responsive to variations in the thickness of the pulp mat and the flow of white water respectively, it is clear that any such -variation will result in longitudinal motion of the shaft 17 9, and hencein an operation of the relay valve 173, which is connected thereto, unless the variations in thickness of the pulp mat and in the flow of white water are such as to maintain the desired ratio of the one to the other. In this event, the rotations of gear 178 and of gear 185 ofli'set each'other so far as the longitudinal motion of the rod 179 is concerned. In order to limit the effective range of motion of the shaft 17 9 and thus to stabilize the-action of the valve 6, the shaft 179 is not directly connected to the relay valve 173, but operates it throu h a mechanism shown in Figures 4 and 7. his mechanism may comprise a member or tooth 189 adjustably secured to the shaft 179 by nuts 190, which engages in a recess between two teeth 191 and 192 on a yoke 193 pivotally mounted as at 194 on a, bracket195. Between the arms 196 of the yoke is pivotally connected a rod 197 which operates the relay valve 173 and thereby'regulates the inflow of pulp through the gate valve 6. It will be apparent that no matter how far up or down the shaft 179 may be moved under the influence of changes in mat thickness or white water flow, or both, the variation in the openin of the gate 6 and hence in the rate of admission of pulp to the container 1, will be limited by the narrow range of motion of the yoke 193 from its neutral position. The mechanism controlling the opening of the gate 6 thus avoids wide fluctuations and serves to maintain a balanced condition of stock concentration in the tester when it is at or near its normal state of equilibrium. The relay valve may be of any preferred type. As shown in Figure 4, it comprises a ball valve 198 which when seated closes the inlet pipe 199 which carries air, water, or other fluid, as preferred under a substantially constant pressure, which may be supplied fromany convenient source. The

valve stem 200 is adj ustably connected to the rod 197 as by a rod 197 screw-threaded or otherwise suitably secured to the rod 197. A resilient connection is preferably interposed between the rod 197 and the valve stem 200 by means of which the ball valve 198 may be held resiliently on its seat against the pressure of the fluid in the inlet pipe 199 when the rod 197, 197 is near its lower limit. The connection as shown comprises a pair of rods 300 extending downwardly from the end. of a cross iece 301 fixed to the lower end of the rod 19 The rods 300 extend through holes in the ends of a cross piece 302 which is secured to the upper end of the valve stem 200, Springs 303 around the rods 300' are compressed between the cross bars 301 and 302. ends of the rods 300 limit the action of the springs and the separation of the cross pieces. The valve stem 200 enters the valve chamber through an aperture 201 large enough to permit the escape of fluid from the valve chamber around the stem. A pipe 202 leads from the valve 173 to the diaphragm motor 172. The operation of the valve is as follows: The rod 197,197 is preferably adjusted so that when theyoke 193 the compression of the springs 303 is light Nuts 304 on the enough to permit some of the fluid under pressure in the inlet 199 to push the ball valve 198 slightly upward and escape into the valve chamber, raising the pressure in the pipe 202 to an intermediate value less than maximum. This pressure in the pipe 202 'actuates the diaphragm valve 172 to open the gate 6 until the pressure on the diaphragm is balanced by the increasing tension of a spring 17 2 or other suitable opposing force. It is desirable to adjust the length of the rod 197, 197, so that the gate 6 willbe held open by the balance of "the i dia hragm 172 a ainst the spring 172 at sue a point as w1 ladmit pulp into thev vat ness of the 'pul at substantiallythe same'rate atwhichit is being removedtherefrom.

rate of supply during thenormal operation of the device. Whenever there is a ohan e in the flow of white water or in the thic mat .unle'ss these changes balance each ot er, there will be a movement of the shaft 179 tilting the yoke'193 and raisingor lowering the rod 197, 197.

' mediate of atmospheric and that in the inlet 7 and is regulated by the rate at which the fluid is permitted to escape past the ball valve. The use of 'fluid pressure in control-' ling the position of the gate 6 makes it possible to locate the tester at any desired aistance from the sampling box.

Should the variation in position of the shaft 179 be excessive owing to some abnormal conditions, the member 189 will travel clear of the teeth 191. and 192. In order to make certain that the teeth will be in position to reengage the member 189 when it returns to its normal range of motion, the yoke 193 is provided with beveled edges 203 against oneof which a plug 204 is adapted to press when the member 189 moves out of range of the teeth. This holds the teeth in proper position for reengagement by the member 189. The plug 204 is fitted into a bore in the bracket 195 and is pressed outwardl by a spring 205 which abuts a screwthree ed plug 206.

Referring to the wiring diagram shown 1n Figure 13, contact points 41, 42 and 43, wlth their spark-absorbing shunts 207 and208, are a part of the hunting mechanism previously referred to which controls the rotation of the motor 44, the armature and field windings of which are indicated at 209 and 210, respectively. 211 and 212 represent high resistance coils which are necessary in operating thefmotor '44 in opposlte dlrections.

The contact points 109, 108 and 110, with their spark-absorbing shunts 213 and 214, likewise control the operation of the motor 101, the armature and field windings of which are indicated at 215 and 216. The

This ,arrangement -of parts avoids see;sawingfof the gate 6 and insures a substantially constant high resistance coils for'use operating the 217 and'218. The motors 101 and 44 are indicated b the- Tdiagram as being series wound. sultable source of electrice'nergy motor in opposite-directions are shown at I isindicated-at'219. The motor 44, as ,pre-'* viouslymentioned, is in series with the limit' stop switches 164 a'n-d"116 5. The motor 101 is likewise in series with the limit stop switches 166 and 167.,

The readings of the scale on plate 143 may be automatically reproduced at an .desired distance vby thejcircuits now, to be escribed. -156 represents the wire carried by the rider 144 which, with'the spring contacts 152m 153, provides an electrical connection between the wires 154 and 155 carried with the plate 143 by the carriage 138. The wire 154 -is a resistance wire ofuniform cross section.

and is connected at its ends electrically through cell springs 220 and 221 to a'battery' 222. The wire 155 is connected to a metal Y piece 223 and coil spring 224 to a lead'. 225

running to a recording otentiometer indicated generally as 226. he springs 220 and 221 permit the travel of carriage 138 alon shafts 131 and 137 with the assembly 0% parts supported thereby, expanding or contractingin conformity to the travel.

' With the battery 222 is provided a resistance 227 with a sliding contact 228 by spection of this circuit, it can be seen that the potential difierence in the recording circuit will be pro ortional to the length of the wire 154 includ d between point 229, which is opposite the zero point of the scale on the plate 14-3,'and point 230 which is equivalent to the position of the pointers 145. The recording potentiometer 226 is of a well-known type constructed to balance automaticall the potential on wire 154 by a contact sli ing on a fine uniform wire 231. The slidin contact 232 automatically records its motion on a chart 233, which may be graduated to read in terms of freeness or of slowness of the pulp, as desired. A recording system of this .which the voltage in the recording circuit 'may be regulated as desired. Froman in- Joe type is not affected the length ofthe leads connecting the recording potentiometer with the varying source of potential, nor is itafl'Tected by the uncertain contact resistances of sliding. spring contacts, since there is no current flowing past such contact points when the system is in equilibrium.-

In Figure 14, I have shown diag rammatically a wiring plan which is designed to provide a-more delicate and reliable link' between the hunting device actuated by changes in the pulpmat thickness and the motor 44. In the practical operation oft-he slowness tester, it has been found that it was necessary for the contact 42 to press against the contact 41 or 43 with substantial force in order to allow suflicient current tofiow to actuate the motor 44. .Since the ratio of motion ofthe end of the fork 3? to that of the measurin roll 22 is approximately 00 to 1, it is evi cut that the necessary pressm force of the contact 42 must be kept as sma l as possible since the magnified force on the sup ortin members 28, 29, and 30, would un uly distort these delicate parts. It is also necessary to avoid any possibllity of the contacts stick'ng as the force aval able to separate them is necessarily very small. The wiring system obviates these difiiculties by means of a relay circuit which operates with a very light touch of the contact polnts and a very small current. The diagram 1n Figure 14 and the description which follows are given by way of illustration only and may be varied as may be required. In the improved relay circuit, the contact points of the hunting device illustrated in Figure 12, are indicated at 41, 42", 43. The contact point 42, which may be moved by the fork 37 into contact with points 41 or 4331s connected to the grid 400 of a triode tube (as for example, radiotron U V 201 A), the plate 401 of which is connected to the positive terminal of a 110 volt D. C. supply through a high resistance relay coil 402. This relay operates to bring into contact with 41' or 43 according as the point 42 touches 41 or 43", the potentials of the latter points being such that when 41 is touched, a moderate plate current from the filament 403 flows through and closes the relay 402 against a suitable restoring force, such for example, as a light spring 409, thereby drawing the point 42 into contact with the point 41', circuit through the armature 209 of the motor 44' and one branch of the field winding 210", and causing the motor to rotate in a direction to operate the follow-up mechanism in the hunting device and restore the fork 37 to its normal position. When the point 43" is touched, a very slight plate current flows, permitting the relay to open and the point 42 to be moved into contact with the point 43", causing the motor 44 to rotate in the opposite direction. If, for example, a -ohm resistance unit be used at 405, a 200-ohm unit at 406, and a 37 5-ohm unit at 407, theresistance of the relay coil being 20,000 ohms, the sliding contact on the resistance unit 406 may be adjusted to 've a filament voltage of 3.5 volts and a potential difference between the filament and plate of 50 to 100 volts. It has been found that such a combination utilizes to best advantage the characteristics of a triode tube. Contact ofthe point 42* with the point 41' will put a potential of about 0 volts onthe grid, giving a plate current of the order of one or two milliamperes which is amply suflicient to close the relay. Contact with the point 43 will put a potential of about the point 42".

closing the- 12 volts on the grid, giving a plate current too small to' keep the re ay c osed. In

neither case does the grid current (which triode, the grid potential does not in general remain constant while the point 42 is moving between 41 and 43", but drifts towards some particular value. A 0.01 microfarad condenser is inserted at 408 to increase the electrostatic capacity of the grid, so that the potential drifts more slowly. A resistance of 10,000 ohms inserted at 404 prevents the condenser charging current from sparking at the contacts. to prevent the possibility of chattering at the contacts being passed on' to the relay. It is evident that since the resistance of the filamentid circuit is very high, the pres sure of t e contacts necessary to close the circuit will be correspondingly minute, and that since the current flowing through the The condenser also serves closed contact is exceedingly low, the ten-.

dency to stick will be negligible.-

It is to be understood that wherever the terms freeness or slowness are used in the claims, either term may be replaced by the other, inasmuch as they bear a simple reciprocal relation one to the other, and that where apparatus for measuring one is claimed, it is intended to include apparatus I for measuring the other.

The disclosure of the invention in the drawings and description is not intended as limiting the invention .in any way but merely as setting forth a preferred embodiment thereof.

What I claim is: Y

1. In a device of the class described, a container for a pulp suspension, means for forming'a mat of the pulp of the suspension,

means for causing the liquid of the suspension to flow through the mat, means for subjecting the mat to a uniform and reproducible compression, and means for indicating variations in the thickness of the mat, said indicating means including a rectilinear scale and a pointer movable relatively thereto.

2. In a device of the class described, a container for a liquid suspension of pulp, means for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to flow through the mat, and means for automatically indicating variations in the flow of the liquid through the mat, said indicating means including a rectilinear scale and a pointer movable relatively thereto.

3. In a device of the class described, a container for a liquid suspension of solid matter, means for forming a mat of the solid matter, means for causing the liquid of the suspension to flow through said mat, and

means for indicating the 'roductfofi the thickness of-the mat-by t e flow of the liquid, said! indicating means'including a tainer for t e pul ear scale and tivel thereto..

4. .a device for determining the free: ness of an aqimoustsuspensmn of pulp, a container for t formin a mat of the pulpof the suspension,

a pointer movable relavmeans or causing the li uid of the] suspension to flow through t e pulp mat, and

means for indicating the 'freeness of the pulp" suspension, said means including a rectilinear scale and a pointer movable relatively thereto-and responsive to the variations of thickness of the pulp mat. r. 5. In a devi for determining the freenes of pulp suspended in a liquid, a container for the pul suspension, means for formin a mat of t epulp of the suspension, means or causing the liquid of the suspension to flow through the mat, and means for indicating the freeness of the pulp, said in-.

dicating means includin a rectilinear scale and a pointer movable rdlatively thereto and responsive to variations in the flow-of the liquid through the mat. 6. In a device for determining the freeness of pulp suspended in a liquid, a container for the pulp suspension, means for formin a mat of the pulp of the suspension, means or causingthe liquid of the suspension-to flow through said mat and means for indicating the freeness of. the pulp, said indicating means including a rectilinear scale and a pointer movable relatively thereto and simultaneously responsive to variations in the thickness of the pulp mat and the flow of the liquid assing .therethrough,

7. In a device or determining the freeness of pul suspended in a liquid, aconsuspension, means for forming a mat of t e pulp of the suspension, means for causing the liquid of the suspension to pass through the mat, and means for indicating the freeness of the pulp, said in-- 'to and simultaneously responsive to variations in the quantity of pulp forming a given area of'the mat, and to variations in the flow of liquid through the mat. V

9. In a deviceof the class described, a 'container for a liquid suspension of pulp, means e pulp suspension, means for eeness of the pulp, said for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension topass through said mat, means for indicating the thic ness of the pulp mat, said indicatin means includin a rectilinear scale mova le in a lateral direction, arider slidabl mounted for motion relative to said scale engthwife thereof, means responsive to variations 'in thickness of the pullp'mat for imparting lateral motion to the sea e, and constraining means engaglng the rider in a manner -to move said rider lengthwise of-the scale during lateral movement thereof.

.10. The combination with'a' container for a liquid suspension of pulp, means for forming a mat of the pulg of the suspension, and means for causing t sion to pass through the mat, of means for indicating the flow of the liquid through so J e liquid of the suspenthe mat, said-indicating means including a rectilinear scale, a rider slidably mounted for movement relative to vsaid scale lengthwise thereof, a member movable in a direction parallel to the scale and responsive to variations in the flow of liquid through the mat, and means operatively connecting said 7 rider with said member.

11.-In a device for determining the characteristics of solid matter suspended in a liquid, a container forthe suspension, means for .forming. the solid matter into a mat,

means for causing the liquid of the suspen:

sion to passthrough said mat, and means for indicating the quality of the suspended material, said indicating means'comprising a rectilinear scale movable laterally, means responsive to variations in the thickness of the mat for imparting lateral motion to the scale, a rider slidably mounted for movement relative to said scale lengthwise thereof, a member responsive to variations in the flow of liquid through the mat and movable .in a

direction parallel to the length of the scale,

and a link engaging said rider and said member in a manner to render said pointer responsive simultaneously to movement of said scale and said member.

12. In a device for determining the freeness of a liquid suspension of pulp, means for formin a mat of the pulp of the suspension, means ar causing the liquid of the suspension to pass through said mat, and means for indicating the freeness of the pulp, said indicating means comprising a rectilinear lat- 'erally movablesca-le, a rider slidably mounted for movement relative to said scale lengthwise thereof, a member movable in a direction parallel to the length of the scale, means engaging said rider and said member in a manner to render said rider simultaneously responsive to movement of said scale and of said member, separate mechanisms for imparting movement to said scale and to said member, oneof said mechanisms of said mechanisms being ness of t e pulp mat, the other mechanism bein responsive to variations in the flow of liqui throu h the mat.

13. In a cfiivice for determining the freeness-of an-a ueous' suspension of pulp, a container for t e pulp suspenslon, means 'for formin a mat of the pulp of the suspension, means ior causing the liquid of the suspension to pass through the mat, mechanism responsive to varia ions in the thickness of the pulp mat, other mechanism responsive to variations in the flow of liquid through the mat and means for indicating the freeness of t e pulp, said indicating means comprising members defining similar triangles having certain of their sides variable, means actuated by the movement of one of said responsive mechanisms for varying the len th of one of said triangle sides, and means or indicating the corresponding length of another said triangle side as a measure of the freeness of the pulp.

14. In a device for determining the freeness of an aqueous suspension of pulp, a container for the pulp suspension, means for forming a mat of the pulp of the suspension, means for causing the liquid of the sus-. pension to pass through the mat, mechanism responsive to variations in the thickness of the mat, other mechanism responsive to variations in the flow of liquid through the mat, and means for indicating the freeness of the pulp, said indicating means comprising members defining two right triangles having variable legs tually similar, means for varying the length of one triangle leg in response to movement of one of said responsive mechanisms, and

means for indicating the corresponding length of another triangle leg as a measure of the freeness of the pulp.

15. In a device for determining the freeness of an aqueous suspension of pulp, a,

container for the pulp suspension, means for formin a mat of the pulp of the suspension, means Tor causing the liquid of the suspension to pass through the pulp, mechanism responsive to variations in the thickness of the pulp mat, other mechanism responsive to variations in the flow of liquid through the mat, and means for indicating the freeness of the pulp, said indicating means comprising members defining two similar right triangles having certain of their sldes variable, means responsive to movement of one for varying a side of one triangle, and means for indicating the corresponding length of a side of the other triangle as a measure of the freeness of the p 1% In a device for determining the freeness of an aqueous suspension of pulp, a container for the pulp suspension, means for forming a mat of the pulp of the suspension,

res onsive to variations in the thick-- but at all times mumeans for causing the liquid of the suspension to pass responsive to variations in the thickness of the pulp, other mechanism responsive to variations in .the'rate of flow of liquid through the mat, and means for indicating the freeness of the pulp, said indicating means comprising members defining a right triangle having variable sides, means responsive to the movement of one of said mechanisms for varying the length of one of the sides of the triangle, and means for indicating the length of another side as a measure of the freeuess of the pulp.

17. In a device for determining the freeness of an aqueous suspension of pulp, a container for the pulp suspension, means for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to flow through the mat, mechanism responsive to variations in the thickness of the mat, other mechanism responsive to variations in the flow of liquid, and means for indicating the freeness of the pulp, said indicating means comprising members defining a right triangle, means for varying an acute angle of said triangle in response to movement of one of said mechanisms, means for varying the length of a leg of said triangle in response to motion of the other of said mechanisms, and means for indicating the length of the other leg of said triangle as a measure of the freeness of the pulp.

18. In a device of the class described, a container for a liquid suspension of pulp, means for maintaining the suspension at a constant level, means for continuously forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to pass through the mat in the course of its formation, mechanism responsive to var1ations in the thickness of the. formed through the mat, mechanism mat, other mechanism responsive to varia-,

tions in the flow of liquid through the mat, and means for indicating the product of the mat thickness by the flow of liquid as a measure of the freeness of the pulp, said indicating means comprising two rods positioned at right angles to each other and defining the legs of a right triangle, a link member pivoted to one of said rods and defining the hypothenuse of said right triangle, a traveler mounted on the other of said rods for movement lengthwise thereof and in sliding engagement with said link member, a rectilinear scale member positioned parallel to the motion of the traveler and movable laterally, a rider slidably mounted for movement relative to said scale member lengthwise thereof and in sliding engagement with the link member, means actuated by the movements of one of said mechanisms for imparting motion to the traveler, and means actuated by the move- I ments of the other said mechanisms for impartin lateral motion to the scale member.

19. device for continuously indicating the product of two variable quantities comprismg in combination, members defining a' right triangle, the elements of which'comprising the sides and acute angles are variable, means for causing one element of said triangle to vary in response to changes in one of the variable quantities, means for causing a second element of said triangle to vary in response to changesin the other of said variable quantities,and means for indicating the magnitude of a third element of said triangle as a measure of the product of the two variable quantities.

20. A device for continuously indicating the roduct of two variables comprising in combination, a rectilinear laterally movable scale member, a rider slidably mounted for motion relative to said scale member lengthwise thereof, an elongated member perpendicular to said scale member; another elongated member parallel to said scale member, a traveler mounted on said parallel member for movement lengthwise thereof, a lever pivoted to saidperpendicular member and slidably engaging said rider and said traveler and defining the portion of said rider on said scale member, means for swinging the lever on its pivot in accordance with the variations of one variable, and means for imparting motion to the scale member in accordance with the variations of the other said variable. y

21. In a device of the class described, a container for a liquid suspension of pulp, means for continuously and separately removing pulp and liquid from the container, means for supplying pulp-and liquid to the container, and means for controlling the consistency of the suspension, said controlling mean comprising means for measuring the.

rate of pulp removal, means for measuring the outflow of the liquid, and mechanical means mechanically connected to both said measuring means for controlling the rate of admission of pulp into the container.

22. In a device of the class described, a container for a liquid suspension of pulp, means for continuously forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to flow through the mat and out of the container, means for admitting liquid to the container automatically controllable to keep the, suspension in the container at a su stantially constant level, means for admitting pulp into the contalner, and means for maintaining a substantially constant ratio of solid to liquid in the suspension, said last means 1 comprising mechanism for measuring. the

thickness of the pulp mat, mechanism for measuring the outflow of liquid, and mechanical means mechanically connected to both mechanisms for controlling the admission of pulp to 'the container.

23. In a devlce for determining the freeness of a li uid suspension of pulp, a cone suspension, means for container for t tmuously forming a mat of the pa] of the suspension, means for causin the llquid of the suspension to pass throug the mat and out of the container, means for measuring the thickness of the formed mat, means for measur ng the outflow of liquid, means for regulating the supply of liquid to the contamer to keep the suspension at a substantially constant level means for indicating the product of the thickness of the mat by the outflow of liquid, said indicating means including a rectilinear scale and a pointer slidable thereon and means simultaneously controlled by both said measuring means for moving the pointer relatively to the scale, and mechanism for maintaining a substantially constant ratio of solid to liquid in the suspension, said mechanism compris I ing a valve for regulating the admission of .pulp to the container and means directly responsive to movement of both said measurmg means for controlling said valve.

24. In a device of the class-described, a container for a liquid suspension of pulp, means for continuously forming a mat of the pulp of the suspension, means for causing the li uid of the suspension to pass through said mat, mechanism responsive to variations in the thickness of the formed mat, other mechanism responsive to variations in the flow of the liquid through the mat, means for automatically controlling the inflow of liquid in a manner to maintain the suspension .at a substantially constant level, and means for controllin the admission of pulp to the container 1n a manner to maintain a substantially constant ratio of solid matter to liquid in the pulpsuspension, said controlling means comprising a reciprocable member having direct mechanical connection with both said mechanisms. l t

25. In a device of the class described, a container for a liquid suspension of pulp, means for continuously forming a mat of the pulp of the suspension, means for cans-- ing the li uid of the suspension to flow through said mat, mechanism responsive to variations in the thickness of the formed mat, other mechanism responsive to variations in the flow of liquid through the mat, means for automatically controlling the inflow of. liquid into the container in a manner to maintain the suspension at a sub:

' stantially constant level, and means for controlling the admission of 111 to the container in a manner to mamtam a substantially constant ratio of solid'matter to li uid in the pulp suspension, said contro g means comprising a threaded shaft having through 9. Ion itudinal slot and mounted for rotation and or motion alon its length, and two are mounted on said shaft and restrained rom motion lengthwise thereof, one of said gears being threaded on said shaft and operatively connected with one of said mechanisms, the other of said gears being constrained to rotate with said shaft by engagement with said slot, and operatively connected with the other of said mechanisms.

26. In a device of the class described, a container for a liquid suspension of pulp, means for continuously forming a mat of the pulp of the suspension,*means for causing the liquid of the suspensiontoi flow the mat, mechanism respossiv m variations in the thickness of "thef fojimed mat, other mechanism responsive lilyg ijlations in the outflow of liquid, means-Ifor regulating the inflow of liquid in a manner to maintain the suspension at a substantially constant level, and means to control the admission of pulp to the container in a manner to maintain a substantially constant ratio of solid matter to liquid in the pulp suspension, said controlling means comprising a reciprocable member mechanically con- .nected directly to both said mechanisms and responsive to an increase in the thickness of the pulp mat to move the reciprocable memberin one direction, and responsive to an increase in the outflow of liquid to move the reciprocable member in the opposite direction.

27. In a device of the class described, a container for a liquid suspension of pulp, means for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to pass through the mat, means for indicating the freeness of the pulp, said indicating means comprising a rectilinear scale member movable laterally between limiting positions, a rider slidably mounted on said scale member for motion lengthwise thereof, a traveler movable in a direction arallel to the length of the scale member etween limiting positions, an means operatively connecting said rider and said traveler; means for measuring the thickness of the pulp mat, means for measuring the outflow of liquid, mechanism controlled by one of said measuring means for imparting motion to said scale member, means for rendering said mechanism inoperative when the scale member reaches either of its limiting positions, another mechanism controlled by the other measuring means for imparting motion to said traveler, and means for rendering said other mechanism inoperative when the traveler reaches either of its limiting positions.

28. In a device of the class described, a

container for a liquid suspension of ulp means for forming a mat of the pu p o the suspension, means for passing the liquid of the suspension through the mat, means for indicating the freeness of the pulp, said indicating means comprising a rectilinear scale member, and a ri er shdably mounted for motion relatively lengthwise thereof; mechanisms for jointly controlling the motion of the rider relative to the scale mem-' ber, oneof said mechanisms being responsive to variations in the thickness of the pulp mat, another of said mechanisms being responsive to variations in the flow of liquid through the mat, an operating electric circuit, and means controlled by the movement of the rider relative to the scale member for varying the potential in said circuit.

29. In a device of the class described, a container for a liquid suspension of pulp, means for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to pass through said mat, and means for automatically indicating the thickness of said mat, said indicating means comprising a hunting member movable from its normal position by change of thickness of said mat, a triode tube having a filament, grid, and plate, a eluding a relay-coil, means controlled by the motion of said hunting member for varying the potential of the id, thereby varying the current through t e relay coil to close the relay or permit it to open, and a motor controlled by said relay to restore said hunt-- .ing member to normal position.

30. In a device of the class described, a container for a liquid suspension of pulp, means for forming a mat of the pulp of the suspension, means for causing the liquid of the suspension to pass through said mat, and means for automatically indicating the thickness of the mat, said indicating means comprising its normal position by change of thickness of said mat, a triode tube having as eled ments a filament, grid, and plate, a circuit certain of said elements and arinvolving be closed by motion of the huntranged to ing member from its normal position, an-

other circuit involving certain of said elements and a relay responsive to the motion of the hunting member, and a motor controlled by said relay for restoring said hunting member ta normal position.

31..The device as set forth in claim 28, but which, in addition, comprises also an electro-responsive recording device connected with said operating circuit.

In testimony whereof I have aflixed my signature.

MILTON O. SOHUR.

plate-filament circuit 1na hunting member movable from 

